LFCS Practice Test 3 — 10 Questions

Question 1

A database server is running out of space in its /var/lib/mysql directory. The system admin wants to add a new 100GB disk to increase storage. Which of the following steps should be performed to mount the new filesystem at /var/lib/mysql without data loss?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Partition the disk, create a filesystem, mount it at a temporary mount point, copy existing data from /var/lib/mysql to the new filesystem, unmount /var/lib/mysql (if it's a mount), mount the new filesystem at /var/lib/mysql, and update /etc/fstab.. It ensures no data loss by first copying existing data to the new filesystem mounted at a temporary point, then unmounting the old mount (if any) and remounting the new filesystem at /var/lib/mysql. This preserves the existing database files and allows the new disk to be used without disrupting the directory structure. The /etc/fstab update ensures the mount persists across reboots.

Answer

Add the new disk as an LVM physical volume, extend the volume group, extend the logical volume containing /var/lib/mysql, and then resize the filesystem.

Answer

Partition the disk, create a filesystem, add an entry in /etc/fstab, and reboot the server.

Answer

Partition the disk, create a filesystem, mount it directly to /var/lib/mysql, and then move the existing data into place.

Question 2

Which THREE of the following are valid methods to mount an NFS filesystem on a client?

Accepted Answer

mount -o hard,intr server:/export /mnt. The `mount` command with `-o hard,intr` specifies NFS-specific mount options: `hard` ensures that NFS operations retry indefinitely until the server responds, and `intr` allows signals to interrupt a hung NFS operation. The command `mount -o hard,intr server:/export /mnt` uses the default NFS version (typically NFSv3) and is a valid method to mount an NFS filesystem on a client.

Answer

echo 'server:/export /mnt nfs defaults 0 0' >> /etc/fstab && mount -a

Answer

mount -t cifs server:/share /mnt

Question 3

A system administrator needs to securely transfer files between two Linux servers using port 22. The administrator uses the following command: 'scp file.txt user@remote:/tmp/'. The transfer fails with the error 'Permission denied (publickey)'. What is the most likely cause?

Accepted Answer

The client's public key is not in the remote user's authorized_keys file.. The error 'Permission denied (publickey)' indicates that the SSH key-based authentication failed. SCP uses SSH for transport, and by default, SSH on the remote server checks the client's public key against the remote user's ~/.ssh/authorized_keys file. If the client's public key is not listed there, the SSH server rejects the connection, causing the SCP transfer to fail.

Answer

The remote server does not have SSH installed.

Answer

The SSH service is not running on the remote server.

Answer

The remote server's firewall is blocking port 22.

Question 4

An administrator wants to change the primary group of user 'jane' from 'staff' to 'developers'. Which command accomplishes this?

Accepted Answer

usermod -g developers jane. The `usermod -g` command changes the primary group of a user. The `-g` option specifies the new primary group (by name or GID), and the user's existing primary group is replaced. This directly accomplishes the administrator's goal of changing jane's primary group from 'staff' to 'developers'.

Answer

usermod -G developers jane

Answer

groupmod -g developers jane

Answer

chgrp developers jane

Question 5

An administrator wants to extend a logical volume named 'lv_data' in volume group 'vg_data' by 5GB. The volume group has free physical extents. Which command should be used?

Accepted Answer

lvextend -L +5G /dev/vg_data/lv_data. The correct command to extend a logical volume is `lvextend`. Option B uses the correct syntax with the `-L +5G` flag, which adds 5GB to the existing logical volume `/dev/vg_data/lv_data`. The volume group `vg_data` has free physical extents, so the extension can proceed without needing to add new physical volumes.

Answer

pvextend -L +5G /dev/vg_data/lv_data

Answer

lvresize -L +5G /dev/vg_data/lv_data

Answer

lvextend -L 5G /dev/vg_data/lv_data

Question 6

Based on the exhibit, what is the correct interpretation?

Accepted Answer

The service is running but the unit file has been modified recently and needs reloading. The 'daemon-reload' notice in the systemctl status output indicates that the unit file has been modified on disk but systemd has not yet reloaded its configuration. Running 'systemctl daemon-reload' will re-read the unit files and apply the changes, which is why option C is correct.

Answer

The service is inactive

Answer

The configuration file is corrupt

Answer

The service is failing

Question 7

A server has two network interfaces: eth0 (192.168.1.10/24) and eth1 (10.0.0.10/24). The default gateway is 192.168.1.1. The administrator wants traffic to 10.0.1.0/24 to go through eth1's gateway 10.0.0.1. Which command adds this route?

Accepted Answer

Both B and C are correct. Both B and C are valid `ip route add` syntax variations that achieve the same result: adding a route to 10.0.1.0/24 via gateway 10.0.0.1 on interface eth1. The `ip route` command accepts the `via` and `dev` keywords in either order, making both B and C syntactically correct. Option D uses the legacy `route` command with improper syntax (missing `dev` keyword before the interface name), which would fail or produce unexpected behavior.

Answer

ip route add 10.0.1.0/24 via 10.0.0.1 dev eth1

Answer

ip route add 10.0.1.0/24 dev eth1 via 10.0.0.1

Answer

route add -net 10.0.1.0 netmask 255.255.255.0 gw 10.0.0.1 eth1

Question 8

Based on the exhibit, what is the most likely cause of the nginx failure and the appropriate first step to resolve it?

Accepted Answer

Check which process is listening on port 80 with 'ss -tlnp' and stop that process.. The error 'Address already in use' indicates port 80 is occupied by another process. Checking with 'ss -tlnp' or 'lsof' identifies the offending process. Option A is incorrect as restarting would fail again. Option C is incorrect because worker_connections affects performance, not binding. Option D is incorrect because MaxClients is an Apache directive, not nginx.

Answer

Restart the nginx service.

Answer

Increase the worker_connections in nginx.conf.

Answer

Reduce the MaxClients parameter in nginx.conf.

Question 9

An administrator configures a systemd service with Restart=on-failure and RestartSec=10. What happens if the service exits with a non-zero exit code?

Accepted Answer

It waits 10 seconds before restarting. When Restart=on-failure is set, systemd only restarts the service if it exits with a non-zero exit code or is terminated by a signal (excluding SIGHUP, SIGINT, SIGTERM, and SIGPIPE). The RestartSec=10 directive then introduces a 10-second delay before the restart attempt, preventing rapid restart loops and giving the system time to stabilize.

Answer

It restarts immediately

Answer

It retries infinitely regardless of exit code

Answer

It does not restart

Question 10

A system administrator notices that a web server is not reachable from the internet but is reachable from the internal network. The server's IP is 10.0.1.10/24, and the gateway is 10.0.1.1. Which command should be used to verify the default gateway configuration?

Accepted Answer

ip route show. The `ip route show` command displays the kernel routing table, including the default gateway entry. Since the server is reachable internally but not from the internet, a missing or incorrect default gateway is the likely cause. This command directly verifies whether a default route (e.g., via 10.0.1.1) is present.

Answer

arp -a

Answer

ip addr show

Answer

ss -tln